Vibrating- contact-belay eor electrical regulators



A. AETIRRILL. 4

VIBRATING CONTACTIRELAY FOR ELECTRICAL REGULATORS.

v APPLICATION FILED SEPT-13,1916. 1,312,503. Patented Aug. 5, 1919.

7 INVENTOR Allen A.Tirrill. -45

" WQW/ ATTORNEY UNITED STATES PATENT OFFICE.

ALLEN A. TIRRILTJ, OF PITTSBURGH, PEIFNSYLVAHIL ASSIGNOR TO WESTIE'GHOUSE ELECTRIC & MANUEACTURING- COMPANY, A COREPGMTION OF PENNSYLVANIA.

VIBRATING- CONTACT-RELAY ELECTRICAL REGULATORS.

Specification of Letters Patent.

Patented Aug. 5, 1919.

Application filed September 13, 1916. Serial No. 119,869.

To all whom it may concern:

Be it known that I, ALLEN A. TinniLn, a citizen of the United States, and a resident of Pittsburgh, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Vibrating Contact-Relays for Electrical Regulators, of which the following is a specification.

My invention relates to electrical'regulators of the vibrating-contact type and it has special reference to relays usually constituting parts of such regulators as are employed for adjusting the field excitations of dynamo-electric machines of large capacity.

More particularly, my invention relates to electrical relays which will respond promptly and Without appreciable time lag to the electrical circuit conditions infiuencing their operation. By means of the present invention, the time-constants of vibrating relays may be adjusted at will, thereby providing means for making electrical regulators of the type mentioned above respond promptly tothe circuit conditions in order to maintain a constant volt-age impressed across the terminals of-a regulated dynamo-electric machine.

Inregulators of the vibratory-contact type it has been proposed heretofore'to employ a relay for intermittently varying the excitation of the vibrating electromagnet of the main control element. Another relay, known as the master relay, is also sometimes provided to control the excitation of the aforesaid relay and a group of auxiliary relays. These auxiliary relays, in conjunction with the other relays, operate in unison and serve to short circuit portions of the resistor in circuit with the field Winding of the exciter. A regulator of this type-having the attendant relays mentioned is shown and fully described in U. S. Patent No. 1,147,574.

To secure prompt response of the exciter to variations in the voltage of the regulated dynamo-electric machine, a plurality of relays must operate in a very short time interval. In other words, the relays associated With the main control element of the regulator must be designed to have a high rate of vibration in order to respond substantially instantaneously to the varying circuit irrespective of the rapidity and the degree of variation of the circuit conditions.

Again, such relays, when-employed in connection with regulators, must operate over a wide range of voltages without affecting their time-constants or their time-rate of response to the circuit conditions upon which their operation depends. When relays heretofore constructed. have been caused to operate at a high rate, the currents required have been so large as to seriously deteriorate the vibrating contacts of the main control element of the regulators.

The object of the present invention is to provide a relay having a small time-constant that will operate over Wide ranges of voltages and, that at the same time, will respond in very short time intervals to the varying excitations to which it may be subjected. Moreover, the present relay doesnot require exciting currents of high value and consequently the vibrating contacts of the main control element may be employed continuously or for an indefinable time without undergoing any serious deterioration.

For a better understanding of the nature and scope of my invention, referencemay be had to the following description and the accompanying drawing in which Figure 1 is a diagram of a vibratory-contact regulator that comprises relays constructed in accordance with my invention; Fig. 2 is a diagram showing a modified structure of the relays embodied in the circuit connections of Fig. 1 Fig. 3 is a simplified diagram. of the novel circuits embodied in the system of Fig. 1, and Fig. .4 is a simplified diagram of the relay and resistors shown in Fig. 2.

An alternating current generator 1 has its armature connected to main'bus-bars or conductors 2 of a suitable distributing circuit and its field magnet Winding 3 connected to exciter bus-bars 4 and 5. Current is sup-- mg 9 is connected in circuit with a resistor 10, suitable intermediary points of which are respectively connected to the contact members of a plurality of relays 11, 12 and 13. The said relays are adapted to operate in unison and, to this-end, are provided with windings 14, 15 and 16, respectively,

that receive current from -the exciter busand 5. The energization of these eggs is controlled by stationary and contact members 17 and 18 of a relay 19 is provided with an actuatinding 20 that is connected through conductors 21 and 22, variable non-inductive resistors 23 and 24 and a conductor,25 to the direct current bus-bars41and 5. The excitation of the relay 19 is varied when main contact inembers 26 and27 of a control element 28 of the regulator. engage and disengage each other. WVhen they engage, the resistor 23 and the winding 20 are shunted or shortcircuited by the circuit comprising a conductor 26", the contact members 26 and 27, the resistor 24 and the conductor 25. The current flow through the winding 20 of the relay 19, is, therefore, discontinued permitting the armature 29 to substantially instantaneously efi'ect engagement between the contact members 17 and 18.

When .the winding 20 and the resistor 23 are short.circuitedthrough the contact memhere 26 and 27, the current flow through the actuating winding 20 is interrupted substantially instantaneouslyby reason of the low time-constant of this circuit which may be controlled by adjusting the value of the adjustable non-inductive resistor 23. Since the actuating winding 20 becomes rapidly decnergized, the armature 211 is promptly released by the relay, permitting engagement between the contact members 17 and 18 to be eflected in a very short time interval. The rate of vibration of the armature 29 may, therefore, be controlled by adjusting the value of the non-inductive resistor 23 which is permanently connected in circuit with the actuating winding of the relay. Since the contact members 26 and 27 control the energization of the relay 19, the armature 29 of the relay will vibrate in unison with the engagement and disengage ment of the Contact members of the main control element 28.

\Vhen the contact members 17 and 18 of the relay 19 engage, which relay I have designated above as the master relay, the actuating windings of the relays 11, 12 and 13 and a relay 30 are short-circuited in a manner similar to the actuating winding 20 of the master relay 19. During the time that the contact members 17 and 18 are disengaged, the actuating windings 14, 15, 16 and 30 are energizedfrom the exciter busbars 4 and 5 through the circuit comprisa conductor 31, a common conductor 32, a group of adjustable resistors, a second group of resistors 32 that are severally connected in series circuit with said actuating windings, a common conductor 33 and a conductor 33.

It will be noted that the group of resistors 32 connected in parallel between the two conductors 33 and 33 and, therefore, when the circuit is established by reason of the engagement of the contact members 17 and 18, the group of resistors 32 is connected stants ofthe several circuits established by short-circuiting the actuating windings of the relays through the noninductive resistor elements, in a manner similar to that explained in connection with the actuating winding of the master relay 19. When the armatures of the relays 11, 12 and 13 vibrate, portions of the resistor 10 connected in circuit'with the field winding of the exciter 7 are short circuited, and by. varying the rate of vibration of the said relays, the effective value of the resistor 10 may be controlled.

lVhen the con-tact members 26 and 27 of the main control element 28 engage and consequcntly short-circuit the actuating winding 20 of the relay 19 through the resistor 23, the resistor 24 limits the current flow through the shunt-circui-t established by the contact members 26 and 27 across the busbars 4 and 5. Likewise, the group of re sisters 32 serves to limit the current flow through the shunt-circuit established by the contact members 17 and '18 when the actuating windings of the relays 14, 15, 16 and 30" are severally short-circuited through their associated resistor elements.

The contact members 26 and 27 of the control element 28 of the regulator are brought into engagement and disengagement by means of two levers 39 and 40 that are controlled respectively by electromagnets 41 and 42. Since the control element 28 is old in the art, further explanation thereof is not deemed necessary, but reference may be had to the U. S. Patent No. 1,147,574 for a detailed description of this form of regulating element.

In order tohave the regulator promptly respond to changes in the circuit conditions in order that the voltage across the tenni nals of the generator may be maintained substantially constant with variations of load, it is essential that the master relay 19, as well as the relays 1'1, 12, 13 and 30, respond substantially instantaneouslyto the changed circuit conditions. tates that the relays vibrate at a high rate of speed over a wide range of energization.

Heretofore relays for accomplishing the above mentioned results had been provided This necessi with expanded heads, such as shown at 43 face area in addition to magnetizing the core member 4.4 to a high degree or to substantially saturation. It was necessary to saturate the core member at the minimum energization of the relay winding so that the relay would vary in operation as little as possible over a very wide range. In order to energize the relay windings to such a degree as to insure that the associated core member would be magnetically saturated under all load conditions, high currents were required which were detrimentalto the arcing faces of the main contact members of the regulator.

I have .found that, by inserting a noninduotive resistance element in series with the energizing winding of the relay when theenergizing Winding thereof is short-circuited by the main control element 28, such as-is shown in Fig. 1, the energization of the relay may be considerably reduced and, at the same time, its time-constant very much lowered. As a result, the value of current flowing across the main contacts 26 and 27 of the main control element is reduced, thereby preventing them from rapidly deteriorating. By adjusting the value of the resistor 23 and the resistor 24, the time constant of the relay 19 may be controlled whereby the vibration of the armature 29 may be increased to a very high rate. For the same reason, the non-inductive resistors 35, 36, 37 and 38 are connected in circuit with their respective relay windings in order to lower the time-constants of the associated relays thereby permitting the regulator to promptly respond to all circuit con ditions. By properly proportioning the value of the non-inductive resistor connected in circuit with the inductive winding 20 of the relay 19, the rate of vibration of this relay may be regulated at will. While the re lay 19 is shown as comprising a U-shaped core member 1-1, it will be understood it may have acore member, such as is embodied in the relays 11, 12, 13 and 30 or other well known forms of core members.

In Fig. 2, l have shown a substitute for the relay 19 of Fig. 1. in this modified relay of the differential type, the energizing.

winding comprises four coilsdti, 17, -18 and 49 that have adjustable taps, as shown, and are arranged in two pairs of parallel connected coils. ()ne pair comprises the coils 46 and 49 and the other pair the coils 47 and 48. The pair of coils 47 and 4 8 are continuously energized because they are located in a circuit including a conductor 50, adjustable non-inductive resistors 51 and 52, a conductor 53, the windings 47 and 48 and a conductor 54..

When the contact members 26 and 27 of the control element of the regulator are in engagement a circuit is established comprising the conductor 50, the resistor 51, an adjustable non-inductive resistor 55, the contact members 26 and 27, a conductor 56, theparallel connected coils 49 and 46 of the relay winding and the conductor 54.

It will be apparent that the armature 29 upon which the contact ,18 is mounted will vibrate asthe encrgization of the core member 44: is varied, as mentioned in connection with the relay 19 of Fig. 1. The contact members 17 and 18 of the master relay serve to short circuit the actuating windings of the auxiliary relays, as hereinbefore eX- plained. i

The resistors and 55 that are connected in circuit with the windings 17%8 and the windings 46-49, respectively, are adjustable in order to control the time constants of the relay 45. By properly proportioning the-several coils comprising the energizing winding of the relay and the resistors 51, 52 and 55, the rate-of vibration of the armature 29 can be controlled.

It will be noted that the resistor '51 is connected in series with "the parallel.connected resistors 52and The resistor 51 serves to limit the current flow through the circuits comprising the relay windings when they are connected in parallel relationship by reason of the engagement of the contact members 26 and 27 of the main control element.

iVhile the relays 19 and 45, as well as the other vibrating relays, are energized from .a direct current source of supply which may be either constant or. varymg potential,

shown in Fig. 1 as'being the exciter 7, the time constants of the relays may be controlled in a similar manner, as mentioned above, when the relay windings are excited from an alternating current source. Refer-ring specially to the relay shown at 45, it should be noted that, by varying the values of the resistors 52 and 55 relatively to each other,'the rate of vibration of the armature 29 may be controlled. Again, underv certaih conditions, where .a high rate of vibration is not essential,'the resistors 52 and 55 may be dispensed with and the time-constants of the relay 45 controlled by properly adjusting the taps upon the several coils of the relay actuating winding.

In Fig. 3, the same reference numerals refor to the corresponding elements of Fig. l, the circuits in this figure being simplified to illustrate clearly the positioning of the non inductive resistors with respect tolthe relay winding 20 and the contact members 26 and 27. F ig. 4 serves the same purpose with r spect to the circuits shown in Fig. 2: v

Vhile I have shown and described several embodiments of my invention, it will be understood that many modifications may be made therein without departin nfrom the spirit and scope of the appended claims.

I claim as my invention:

1. In a voltage regulator, a relay having two differential windings and a pair of contact members, a. resistor connected in series with one of said windings, a second resistor adapted to be connected in series with the second winding and in shunt t0 the first winding and the resistor associated therewith by the relay contact members, and a resistor in circuit with the two windings.

2. In avibrating relay, twov windings, two adjustable resistors severally associated with said windings, a third adjustable resistor, and means controlled by the relay contact members for connecting thetwo windings and the resistors associated therewith in parallel relation and the third resistor in series with the two windings.

3. In a regulator, a relay having two balanced differential windings, two adjustable resistors adapted to be connected severally in series with said windings, a third resistor adapted to be connected in series with the two windings, and means embodying the relay contact members, one of said windings and the resistor associated therewith for ential windings mounted on the core member, one winding being continually energized and the other'winding being intermittently energized, two non-inductive resis tors severally connected in series with said windings, and a third non-.inductiveiresistor in series with the two windings for lowering the time constant of the relay and for preventing the sticking of the relay contact members.

5. In a voltage regulator, a relay embody ing two diflerentia-l windings, two resistors severally associated with said windings, one

of said windings being normally energized, and means for connecting the second wind ing and the resistor associated therewith in shunt circuit to the normally energized winding and the resistor associated therewith when the relay is operated.

6. In a regulator, a vibrating relay comprising two windings, one of said windings being normally energized, a resistor in series circuit with the normally energized winding, a second resistor adapted to be con-- nected in series circuit with the two windings, and means for shunting the normally energized winding and the resistor associated therewith by the second winding.

, In testimony whereof, I have he to subscribed my name this z3d day of August,

ALLEN A. TIRRZ 

